In digital content delivery systems, multimedia content is broadcasted to user devices by a broadcasting unit through communication channels.
During transmission of the signals from the broadcasting unit to the end user devices, errors might appear in the multimedia content, due to bad conditions in the transmission channels, and consequently the user might receive corrupted content.
Conventional systems are known to detect and/or correct radio transmission errors, such as Forward Error Correcting (FEC) systems. These systems are implemented on the user devices. Such systems are based on a modification of the very multimedia content by adding redundancy to the original information bits. With FEC codes, a user device can directly correct transmission errors. However, the redundant bits added to original information bits reduce the gross bit rate of transmission. Further, FEC systems only allow corrections of errors due to a limited number of reasons such as noise or interference. Therefore, data might be received with insufficient quality.
Other solutions are known that allow retransmission of data that has not been received in the original transmission either through the broadcasting channels or through a dedicated point-to-point channel. The user device reports any missing data to the broadcasting unit, and the broadcasting unit accordingly retransmits the missing data to the user device. Such solutions ensure that all the data will be received by the user devices. However, they require a huge amount of bandwidth for retransmitting simultaneously the data to all the end users.